Hi Alan, hi list, I appreciate the tables explaining the compatibility of authentication systems / protocols to password type compatibility from: [table 1] http://deployingradius.com/documents/protocols/compatibility.html and [table 2] http://deployingradius.com/documents/protocols/oracles.html But I am still confused about the relationship of these two tables to each other and how to use them. Is the following considered correct? 1. If I am using the back end DB (e.g. ldap or users file, etc.) as a simple *password store*, only [table 1] if of interest. And freeradius is able to connect to the back end (if there is a rlm_<back-end-db> module available), authenticate itself with a special radius server account/user credential and to retrieve the password plus optionally some other attribute values if the radius server *itself* authenticates successfully with the back end DB. The radius server itself is then performing the user name/password check to accept or reject the authentication request of the user trying to connect. 2. If I am using the back end DB (e.g. ldap etc.) as an *authentication oracle*, [table 2] tells me which authentication oracle system I can use (depending on the authentication protocol that the supplicant/client/user is using) and [table 1] tells me in which format the passwords need to be stored in the authentication oracle. And freeradius is able to connect to the back end (if there is a rlm_<back-end-db> module available), to authenticate *with the user provided* credentials (username/password) and to optionally retrieve some attribute values if the *user* authenticated successfully against the authN oracle. Confirmation or further clarification is welcome. Thanks Reimer ps: There is probably a small typo in the column heading of [table 1]: 'SSHA1 hash' should be 'SHA1 hash' and 'Salted SSHA1 hash' should be 'Salted SHA1 hash (SSHA1)' -- Kind Regards Reimer Karlsen-Masur DFN-PKI FAQ: https://www.pki.dfn.de/faqpki -- Dipl.-Inform. Reimer Karlsen-Masur (PKI Team), Phone +49 40 808077-615 DFN-CERT Services GmbH, https://www.dfn-cert.de, Phone +49 40 808077-555 Sitz / Register: Hamburg, AG Hamburg, HRB 88805, Ust-IdNr.: DE 232129737